Following the advance of manufacturing techniques in semiconductor industry, the density level of integrated circuit has been largely upgraded. BGA (Ball-Grid Array) packaged chips have been adopted broadly in many aspects of integrated circuit packaging technique.
This packing method is explained as follows and the illustration is shown in FIG. 1. Referring to FIG. 1 shown as a cross-sectional diagram, a semiconductor die 20 being cut from a wafer is attached with a substrate 10 by an adhesive layer 22. A solder mask 12 overlays the substrate 10 for electrical isolation as well as preventing conductive material from oxidation. A plurality of bounding wires 18 are used to connect the semiconductor die 20 with the conductive traces 14. Afterward, a resin layer 19 is formed upon the substrate 10 through molding process to cover and protect the semiconductor die 20 and the bounding wires 18. On the other hand, a plurality of solder balls 28 are welded on solder pads 30 and then the solder pads 30 are coupled electrically to the via 16. By using the conductive traces 14 as a link the via 16 are connected electrically with the bounding wires 18 so as to complete chip-packing process. Finally attach the solder balls 28 to a plurality of solder pads 36 welded on printed circuit board 34 so as to connect electrically the packaged chip and printed circuit board.
After the packaged chip has been adhered on the PCB, testing is performed to check whether the function of the chip is correct. If the testing results indicate that the chip has errors wherein, we have to carry out the following steps:
Establish a temperature curve for each error packaged chips.
Pick up these error packaged chips.
Rid the residual soldering paste and cleaning the area of error packaged chips that have been picked up.
Replace a new packaged chips for same testing.
Reflow weld these new packaged chips.
Generally, the picking-up procedure is authorized to the specialized companies because they have sophisticated testing equipments and plentiful resources. In addition to outsourcing, purchasing picking-up equipment is another way. However both the two approaches are costly and will burden the company a lot. Hence, in practice some companies pick the chips up using some simple tools, such as pliers, nippers, even their hands. Due to the crudeness of the tools, the solder pads of the printed circuit board are easily torn while picking the chip up. Therefore, it gives us a strong incentive to create an economical apparatus for picking packaged chips up from the PCB.